After a period of relative neglect in many countries, apprenticeships and other forms of work-based learning are experiencing a revival, in recognition of their effectiveness in easing school-to-work transition and serving the economy. Apprenticeships typically involve a structured mix of: 1) time spent at a workplace, during which apprentices develop skills and perform productive work; and 2) off-the-job training and education which is typically overseen by public authorities. In most countries, apprentices spend more than 50% of their time in the workplace. Apprenticeships lead to formal, nationally recognised qualifications. The challenges, however, of engaging individuals, employers, social partners and education and training systems in such learning are significant. This synthesis report draws out policy messages on how to design and implement high-quality apprenticeships using material from the OECD project Work-based Learning in Vocational Education and Training. It draws on analytical work conducted throughout the project and policy messages set out in six published policy papers. It poses seven questions commonly asked by governments seeking to either introduce or reform apprenticeship systems for young people and/or older workers: 1) can apprenticeships provide a useful contribution in every country? 2) Should employers receive financial incentives for providing apprenticeships? 3) What is the right wage for apprentices? 4) How long should an apprenticeship last? 5) How can a good learning experience at work be ensured? 6) How apprenticeships can be made to work for youth at risk? and 7) How to attract potential apprentices?